Transitioning from traditional time-division multiplexing (TDM) trunks to voice over IP (VoIP) centralized session initiation protocol (SIP) telephony services provides many enterprise organizations significant savings. The SIP is a communications protocol for signaling and controlling multimedia communication sessions. The most common applications of SIP are in Internet telephony for voice and video calls, as well as instant messaging, all over Internet Protocol (IP) networks. Voice transmission of telephony using IP networks is referred to as voice over internet protocol, or voice over IP (VoIP). TDM is a method of transmitting and receiving independent signals over a common signal path by means of synchronized switches at each end of the transmission line so that each signal appears on the line only a fraction of time in an alternating pattern.
A limitation of this transition is the use of the data network at each location to carry voice (or video) transmissions, adding to the bandwidth of transmissions. There is a limit to the number of concurrent voice transmissions that can be carried on the local and wide area data networks, based on the bandwidth at each location when the IP data service provided includes quality of service (QoS) based multi-protocol label switching (MPLS) networks. MPLS is a scalable, protocol-independent transport, often chosen for reliability purposes, in which data packets are assigned labels. Packet-forwarding decisions are made solely on the contents of this label, without the need to examine the packet itself.
Configurations for enterprise-level data and voice transmissions often have a capacity limitation at each of a plurality of locations, for example a consulting business may have multiple branch locations as well as a headquarters location. Each branch location may have a designated number (fixed limit) of concurrent voice transmissions assigned as a threshold limit, based on the number of employees at each location. Extra capacity may be assigned to accommodate peak periods, but the extra capacity may go unused for a majority of time. Alternatively, without establishing extra capacity, peak voice transmission periods may experience loss of service.